format code with gofumpt

gofumpt (https://github.com/mvdan/gofumpt) provides a supserset of `gofmt` / `go fmt`,
and addresses various formatting issues that linters may be checking for.

We can consider enabling the `gofumpt` linter to verify the formatting in CI, although
not every developer may have it installed, so for now this runs it once to get formatting
in shape.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

notifications/bridge_test.go

@@ -233,7 +233,6 @@ func checkCommon(t *testing.T, event events.Event) {
 	if event.(Event).Target.Repository != repo {
 		t.Fatalf("unexpected repository: %q != %q", event.(Event).Target.Repository, repo)
 	}
-
 }
 
 type testSinkFn func(event events.Event) error